Evolving cashew F1 hybrids suitable for high density planting system

Abstract

Hybridization and selection experiment was carried out in cashew to evolve a compact or dwarf F1 hybrid suitable for high density planting system, which is the utmost need to improve the productivity of cashew nuts in the country. Eight promising hybrids with tall, semi-tall or dwarf stature were selected from the crosses and evaluated for morphological parameters and stomatal density. The results revealed that the hybrids HC 6 was dwarf with 3.0 m height, reduced number of primary and secondary branches, number of leaves per current season’s shoot (5.3), reduced internodal length (0.25 cm) and number of internodes (5.3). HC 6 also recorded a higher number of stomata (57.2 per mm2). The highest cumulative yield for three years was recorded in HC 1 (3.5 kg nuts per tree) followed by HC 6 (2.65 kg nuts per tree). HC 1 was semi-tall and compact. Correlation studies revealed that there is strong positive correlation between plant height and length of current season’s shoot, number of internodes per shoot, intermodal length and number of branches. This study resulted in a hybrid with reduction in height, number and length of internodes, spur formation on shoots, reduced leaf size, number of shoots with moderate yield. However, the genetic nature of dwarfness is to be confirmed by further evaluation through conventional breeding and molecular approaches.